Bump pygments from 2.6.1 to 2.7.4 (#77)

Bumps [pygments](https://github.com/pygments/pygments) from 2.6.1 to 2.7.4.
- [Release notes](https://github.com/pygments/pygments/releases)
- [Changelog](https://github.com/pygments/pygments/blob/master/CHANGES)
- [Commits](pygments/pygments@2.6.1...2.7.4)

Signed-off-by: dependabot[bot] <[email protected]>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

requirements.txt

@@ -1,6 +1,6 @@
 djangorestframework==3.11.2
 Django==3.1.6
-Pygments==2.6.1
+Pygments==2.7.4
 Markdown==3.2.1
 coreapi==2.3.3
 psycopg2-binary==2.8.4